Carburetor



Fd@ Mi 1938; F. o. BALL. ET A1. 2,108,281

CARBURETOR Filed April 2, 1934 2 sheets-'sheet 2 INVENTOR, FRL-'05mm o. ,sA/1. mvo BYrHaM/la M. BALL..

Patented Feb. 15, i938 PATENT orner.

'amasar Y empataron Frederick ommsna'rnom'nnmneirds.'

A man. a

. 4applicata Apxu 2,1934.' sei-a1 No. 'us'.s'ze

' 's anima (ci. :s1-s4) This inventionrelates fuel feeding devices for internal combustion engines.

More particularly the invention provides improved apparatus commonly called pick-up pump mechanism for temporarily augmenting the sup. ply of fuel to an internal combustion engine during accelerating the speed of operation thereof.

One of the main objects of the invention is to.

provide improved apparatus of this character vwhich is adapted to promptly supply an initial augmenting charge of fuel to the fuel system of an internal combustion engine during opening of the valve thereof, and to subsequently supply del layed augmenting charges thereto at different rates of discharge during a limited period follow- .ing cessation of the opening movement of the throttle valve. j

Other objects of the invention are to provide a primary fuel displacing member in apparatus of this character which is adapted to discharge fuel both during and after throttle opening movements; to provide a secondary fuel displacing means which is adapted to discharge fuel at 'a different rate than said primary fuel displacing means after operation of the latter is dis.

continued; to provide a secondary fuel displacing means of this kind which is adapted to operate a valve for controlling the flow of fuel from a pick-up pump mechanism; and to provide fuel displacing members, one adapted to displace a delayed discharge of fuel immediately after opening movement of the throttle is discontinued,

and the otber being adapted to displace a further delayed discharge of fuel at a lower rate after the first mentioned displacing means is inoperative.

Other objects of the invention are to provide means in apparatus of this character for delivering the augmenting fuel charges to the fuel mixture intake passage of a fuel system independently of the normal liquid fuel feeding means; to provide means for preventing a flow of fuel from the charge augmenting apparatus when the latter is not operating; to provide valve mechanism for this purpose which is' adapted to be i pened by the pressure applied on the fuel charge uring initial movement of the throttle valve toard an open position; to provide means in valve o echanism of this character which is adapted o prolong the delayed discharge until the augw enting charge valve is completely closed; and provide operating mechanism for a valve of his kind which is adapted to limit and relieve he pressure created during rapid throttle openmovements.

Further objects of the invention are to provid means in a pick-up pump mechanism for limiting opening of the augmenting charge valve when the throttle valve is opened rapidly so as to prevent overloading of the carburetor with fuel and 5 to preserve some of the fuel for the delayed discharges; and to provide means and 'apparatus of this kind for decreasing the discharge of fuel when the carburetor throttle in commotion with which it'operates is opened to a desired extent.v 10

. Illustrative embodiments of the invention are shown in" the accompnying drawings, in which:

Fig. 1 is a side lelevational view of a carburetor partly in vertical section showing our improved pick-up pump. Y 15 Fig. 2 isa fragmentary vertical sectional view taken on the line II-II of Fig. l.

Fig. 3 is a vertical sectional view taken on the v line III- III of Fig. 2. V

Fig. 4 is a vertical sectional view taken on the 20' line IV--IV o f Fig. 1.

Fig. 5 is a fragmentary sectional view of a carburetor showing a pick-up pump that embodies a modified Vform ofthe invention, in an inoperative condition. 25.

Fig. 6 is a view similar to Fig. 5 showing a picklup pump mechanism in an operativevposition.

Fig. '1 is an enlarged, fragmentary sectional view of the pistons embodied in the form of the invention illustrated in Figs. 1 to 4, inclusive, 30

showing the latter in changed position.

a In the form shown, a carburetor in which' our improved pick-up mechanism is illustrated is of the down-draft type. The pick-up mechanism vmay, however, be incorporated in an up-draft 35 I2 and an` outlet I3 for delivering fuel mixture d to an intake manifold of an engine (not shown). The body portion I0 of the carburetor isprovided with a fuel reservoir I4 having an inlet I6 which is controlled by a valve I6. The valve I6 is operated by conventional float mechanism I1 which 45 predetermines the fuel level in the reservoir.

Formed on one side of the carburetor is a pickup pump cylinder I8 having a cylindrical bore I9 in which a hollow piston 20 is slidably mounted. The outer periphery of the piston 20 50 fits tightly against the inner. peripheral wall of the bore I9 of the cylinder and it is provided with a central, axially extending passage 2i in., which a second hollow piston 22 is slidabiy mounted. The piston 2li has a spider 23 extending across 55 end 'of the inner and smaller piston 22 is a valve the upper end of the passage 2l in which a rod 24 of the pump actuating mechanism is slidably mounted.

The pump actuating mechanism includes a lever arm 25 non-rotatably xed to one end of a rotatable throttle valve shaft 28 having a throttle valve 21 thereon disposed in the outlet end portion I3 of the fuel mixture passage Il. The rod 24 is operatively connected with the lever arm 25 by an L-shaped bar 28 slidably mounted in a passage 23 in the body portion I0 of the carburetor and a connecting link 30 pivotally attached to the lower end of the bar 28 and to the lever arm 25. Concentrically mounted on the rod 24 is a coil spring 24 which bears between the upper end portion of the shiftable bar 28 and the spider 23 of the piston 20 in such a. manner as to yieldably urge the piston downwardly as viewed in Figs. l and 2 when the throttle valve 21 is opened by conventional throttle valve operating apparatus generally designated by the numeral 21'.

The pump cylinder I8 is provided with a fuel inlet 3| communicating at one end with the interior of the fuel reservoir I4 and having an outlet 32 communicating with the interior of the 4pump cylinder. The outlet 32 is normally closed by a ball valve 33 adapted to open during thesuction stroke of the piston'20 to admit fuel to the interior of the cylinder. Formed in the bottom wall 6i the cylinder I8 is a threaded aperture 34 in which a plus 35 is mounted. 'I'he plug 35 has a central passage 36 communicating with a passage 31 extending along the side wall of the cylinder I 8 and leading to an inlet port 38 which is preferably provided at the section of maximum constriction with a venturi 39 formed in the fuel mixture passage II. A threaded metering plug 4U is disposed in the outlet 38 to regulate the quantity of fuel discharged from the pick-up mechanism.

Slidably mounted in an aperture in the lower stem 4I which is adapted to normally close the passage 36 constituting the outlet of the cylinder I8 both during the suction strokeof the piston 20 and while the fuel displacing members thereof are inoperative. The valve stem 4I has a head disposed in the interior of the hollow piston 22 .engageable by a set screw 42 which is threaded in the lower end of the latter piston. The set sc`rew 42 may be adjusted axially of the hollow piston 22 for the purpose oi .varying the distances between the lower end of the rod 24 and the upper end of the set screw 42 so as to limit the lift of the piston 22 fox-wide open pick-up and predetermine the back-lash of the valve stem 4I.

In the form of the invention shown in' lFigs. and 6, the general construction of the pick-up pump mechanism is substantially the same as that shown in Figs. 1 to 4, inclusive, and identical parts of the structure are designated by the same numerals employed in the description of the latter figures.

In this form of our invention a piston 43 is slidably mounted in the cylinder I8 and operatively connected with throttle valve control apparatus by a rod 24, spring 24 and L-shaped shiftable bar 28. The rod 24 is fixed to the upper end of the piston 43 and slidably mounted in an aperture formed in the bar 28. The piston 43 has an axially extending passage extending from its lower extremity to an upper end wall 44 having an aperture 45 in which the rod 24 is slidably received. Formed in the side wall of an upper circumferentially relieved portion of the piston 43 are openings 46 which communicate with the axially extending passage thereof. Slidably mounted in the axially extending passage of the piston 43 is a second hollow piston 41 having a lower end wall 48 provided with fuel passages 49 leading to the interior thereof and having a valve stem 4I for closing the outlet passage 38 of the cylinder. The upper end of the piston 41 is closed by a cap 5B and the side wall portions adJacent its upper end are provided with ports 5I which are adapted to register with the openings 46 in the side wall of the piston 43 when the piston 41 is in' its retracted position so as to permit by-passing of fuel from the pressure end of the piston 43 -to the opposite end thereof through the passages 43, interior of the piston 41, and openings 5I and 46 of the inner and outer pistons, respectively, as illustrated in Fig. 6 of the drawings. Alspring 56 bearing between the upper end of the-piston. and the end wall 44 of the piston 41, normally urges the latter outwardly from the piston 43. i

In operation of the pick-up mechanism illustrated in Eigs. 1 to 4, inclusive, the space at the lower end portion of the cylinder I 8 is normally maintained filled with fuel supplied through the passage 3I and inlet 32 during upward movement of the piston 2li accompanying throttle valve closing operations. This fuel is prevented from escaping from the lower end portion of the cylinder I8 by the valve 4I During initial throttle `valve opening movements the shiftable L- shaped bar 28 is urged downwardly thereby subjecting the spring 24' to compression and in turn urging the piston 20 downwardly. The downward movement of the piston is opposed by uid contained in the lower end of the cylinder I8 which acts upon the inner piston 22 causing it to be forced upwardly into the interior of the piston 20 thereby lifting the valve stem 4I from its seat and permitting displacement of fuel from the cylinder to the fuel mixture passage of the carburetor. During moderately rapid opening movements of the throttle valve the resistance to downward movement of the piston 2l offered bythe fuel in thecylinder causes the downward movement of the bar 24 to exceed the downward movement of the piston and the spring 24' is placed under compression.

When opening movement of the throttle is discontinued, the spring expands and urges the piston 20 downwardly-until the spider 23 engages the head formed on the lower end of the rod 24, thereby providing a delayed discharge of fuel throughout a limited period after opera on of the pump actuating mechanism and thrott e con-v trol apparatus has discontinued. When the piston 30 ceases to apply pressure on the fuel in the lower endportion of the cylinder I8, the inner piston 22 moves downwardly under the action of gravity thereon until the valve stem 4| engages the plug 35 and closes the outer passagel ing excessively rapid throttle valve opening moven ments, the lower end of the rod 24 of the pump actuating apparatus engages the upper end of the set screw 42 and thereby limits opening of valve 4I suiiiciently to prevent' an excessive amasar initial discharge of fuel. In this manner opening of the throttle to bring about acceleration of an internal combustion engine is accompanied nya temporary initial augmenting charge and by two stages of delayed augmenting discharges of fuel which may be so controlled as to prevent overloading and to also insure the supply of sufiicient fuel during that critical stage' of internal combustion engine operation immediately following opening of the throttle valve of the carburetor-thereof. l

The modified form of our improved pick-up pump mechanism illustrated in Figs. and 6 operates in many respects substantially the same as the pick-up pump mechanism shown in Figs. `1 to 4, inclusive. The initial downward movement of the outer piston 43 accompanying initial throttle valve opening movement raises the inner piston 41 sufficiently to open the valve 4|. The spring 24' is placed under compression during the valve opening movement and expands thereafter effecting a delayed discharge of fuel by the piston 43 and the piston 41 descends from its retracted position under the action of gravity producing a further delayed discharge of fuel after movement of piston 43 ceases. In the event, however, of--an 'excessively rapid opening movement of theethrottle valve, the inner piston 41 is retracted to the position shown in Fig. 6 and the ports 5|. thereof register with the openings 48 of the outer piston 43 and permit bypassing of fuel from the pressure end of the `i'uel displacing means to the opposite end thereof, in this way decreasing the pressure and the discharge of fuel so as to guard against overload` ing of the carburetor and fuel system of the internal combustion engine with which it is associated. l'

, Although but several specific embodiments of the invention are herein shown and described, it will be understood that various changes in the size, shape, and arrangement of parts may be made without departing from the spirit of our invention, and it is not our intention to limit its scope other than bythe terms of the appended claims.

We claim: 1. Ina carburetor, pick-up pump mechanism including a fuel chamber having an outlet for supplying fuel to an internal combustion engine V fuel mixture passage, a fuel displacing member in said chamber, means for normally closing said outlet including a valve and an element responsive to the' pressure'applied on the fuel of said chamber by said fuel displacing; member for holding said valve in open position, and apparatus for operating said fuel displacing member having a resilient element constructed and -arranged to continue the fuel discharging operation thereof afteractuation of said operating apparatus is discontinued and including an ele-- ment movable relative to said uid displacing member constructed and arranged to limit the opening of said valve when said operating apparatus is actuated rapidly.

2. In a carburetor, pick-up pump mechanism including a fuel chamber having an outlet for supplying fuel to an internal combustion engine fuel mixture passage, a fuel displacing member in said chamber, means for normally closing said outlet including a valve, apparatus for operating said fuel displacing member having a yresilient element constructed and arranged to continue the fuel discharging operation thereof after actuation of said operating apparatus is discontinued and including an element movable relative to said iluid displacing member constructed and arranged to limit the opening of said valve when said operating apparatus is actuated rapidly.

3. In a carburetor having a fuel mixture passage, a throttle valve for controlling the flow of fuel mixture from said passage, apparatus for regulating said throttle valve, a pick-up pump mechanism including a fuel chamber having an outlet communicating with said fuel mixture passage, a fuel displacing member in said chamber, means operable by said throttle control apparatus for actuating said member during throttle opening movements, 'and including a resilient element for continuing operation of said member for a limited period' after said opening movement of said throttle is discontinued, a member for normally closing said outlet including a valve adapted to be opened by the pressure of the fuel in said chamber, said means having, an element engageable with said valve for limiting opening movement thereof when said throttle is widely opened.

4. A pick-up pump including a pump cylinder I having a fuel inlet and outlet,telescoping pistons in said cylinder for displacing fuel therefrom, means for actuating the outer piston, the inner piston being energizable by the pressure of the fluid in said cylinder and having a passage therethrough communicating at its ends with the spaces in said cylinder on respectively opposite ends of said outer piston for by-passing fuel from 'the pressure lend to the opposite end of said cylinder during rapid operation of said actuating means. l

5. A pick-up pump including a cylinder having a fuel inlet and an outlet, a hollow piston in said cylinder for displacing fuel therefrom. a second piston slidablymounted in said ilrst piston havingby-pass orifices in its respectively opposite ends, the-.by-passv orifice of one end of said second piston being formed in the side wall thereof and adapted tobe closed by the wall of said first mentioned piston when said second piston is in an extended position, said second piston being` movable to a retracted position by a predetermined pressure of the fuel in said cylinder so as toVby-pass fuel from one end to the other end of said pistons for .controlling the fluid pressure in said cylinder.

-8. A pick-up pump including a cylinder having a fuel inlet and an outlet, a `piston slidably mounted in said cylinder for displacing fuel therefrom and having a passage therethrough, means for operating said piston, a valve element slidably mounted in said passage for normally closing said outlet, said valve element being movable to a retracted position by the pressure of the fuel in said cylinder and being provided with a passage for by-passing fuel from the pressure end of said cylinder to the opposite end thereof, one end of said by-pass passage being closed by the wall of the passage in said piston when the pressure in said cylinder is below a predetermined value.

'7. Pick-up pump mechanism including a pump cylinder having an outlet, an outer hollow piston slidably mounted in said cylinder having its open end facing said outlet and having wall edge portions for displacing fluid from said cylinder, the interior of said vouter piston being vented, an inner piston slidably mounted in said outer piston and having a head portion facing said outlet for discharging fuel from said cylinder, a valve carried by said inner piston for controlling said 8. Pick-up pump mechanism including a pump cylinder. having an outlet passage, an outer hol-v low piston slidably mounted in said cylinder hav ing its open end facing said outlet and Ahaving wall edge portions for displacing uid from said cylinder, the interior of said outer piston beinl vented directlyvto the low pressure end of said cylinder, an inner piston slidably mounted in said outer piston and having a head portion facing said outlet paage for discharging fuel from said cylinder, a Valve carried by said inner piston normally closing the internal end of said outlet passaseand constructed and arranged to open the latter in response to movement of said inner piston away from said outlet, said inner piston being movable away from said outletby 10 the pressure applied on thefuel.

FREDERICK o. 'BALL THOMAS M. BALL 

